"K"
Reference:
48557
Block A, First Floor, 1 On Langford,
Langford Road, Westville,
Republic of South Africa, 3629
PO Box 670, Westville, 3630
Tel:
+27 (0)31 240 8860
E-mail: [email protected]
Web:
http://www.wspgroup.co.za
24 May 2017
Upper Highway Air NPO
19 La Vigna
Plantations Estate
Hillcrest
Attention:
WSP Environmental (Pty) Ltd
WSP Environmental (Pty) Ltd
Registered Number: 1995/08790/07
A member of the WSP Global Inc.
Offices worldwide
Charmane Nel
RE: AMBIENT AIR QUALITY TESTING NEAR ENVIROSERV SHONGWENI LANDFILL
Members of the WSP Environmental Air Quality team conducted air quality testing adjacent to the
western fenceline of the Enviroserv Shongweni Landfill (Figure 1) during the early afternoon of the
8th of May 2017. The wind was blowing in a north-easterly direction during sampling. The sun was
shining and there was approximately 20% cloud cover. While the team detected a landfill smell
during the sampling session, it was agreed that this was not at the high intensity experienced on
some previous visits to the fenceline. My personal description of the smell was ‘typical rotten egg
(hydrogen sulphide) landfill smell combined with petroleum-type hydrocarbons’.
Figure 1: Sampling Location
Three cubic decimetres (3 dm3) of air was pumped through two Markes International sorbent tubes
(G0129825 and G0129891). A sample blank (G0129826) was also collected. This methodology is
in accordance with the United States Environmental Protection Agency (US EPA) TO-14a. The
sample blank (G0129826) was collected first followed by the two 15-minute samples at 200
ml/minute – G0129825 (12h50 - 13h05) and then G0129891 (13h10 - 13h25). Pump flow rates
were controlled internally but were checked against a Bios Defender standard prior to use. The
three tubes were transported directly from the site to Skyside (Pty) Ltd in Riverhorse Valley,
Directors:
SL Doel#(Managing), MC du Plooy**, JH McStayB, ESBF Mtetwa* (non-Executive)
Ver: Nov 2015
(# Pr Sci Nat) (* Pr Eng) (** Pr Tech Eng) (B British)
Durban, from which they were transferred for analysis at X-Lab Earth Science (Pty) Ltd in Randburg
(SANAS Accredited Laboratory number T0775). The samples were received by X-Lab in Randburg
on the 11th of May 2017. The samples were screened for a full spectrum of volatile organic
compounds. Analysis commenced on the 15th of May 2017 at 10h55 and was completed on the
15th of May 2016 at 15h16. Results were signed off by Martin Olivier, Operations Manager at XLab. The gas chromatography-mass spectrometry (GCMS) component of this analysis falls under
X-Lab’s current accreditation. While X-Lab conforms to ISO/IEC 17025 standards, the thermal
desorption component of these analyses currently falls outside of the scope of X-Lab’s
accreditation. I am not aware of another local laboratory that is accredited for this technique.
Results are presented in Table 1 and Table 2 below, accounting for the measurements on the
sample blank (G0129826). The only volatile organic compound with a National Ambient Air Quality
Standard (NAAQS) is benzene with an annual NAAQS of 5 µg/m3 (0.005 µg/dm3) or 1.6 ppbv
(0.0016 ppmv). For assessment of health impacts, volatile organic compounds generally are
compared with long-term (annual) guidelines. These are not appropriate here due to our short (15minute) sampling period. The Texas Commission on Environmental Quality’s (TCEQ) provides
Effects Screening Levels (ESLs) for short-term (generally hourly) exposures. These ESLs were
developed from data on health effects, vegetation or corrosion effects and odour nuisance potential.
If the predicted ambient concentrations do not exceed these levels, no adverse environmental or
health effects are expected. Benzene concentrations as measured by G0129891 exceeded the
TCEQ short-term ESL (170 µg/m3). The concentrations of m/p xylenes as measured by G0129825
and G0129891 also exceeded the TCEQ short-term ESL (2200 µg/m3). The concentrations of
styrene as measured by G0129825 and G0129891 exceeded the TCEQ short-term ESL (110
µg/m3) as well as World Health Organisation (WHO)1 guidelines of 260 µg/m3 (weekly average for
health impact) and 70 µg/m3 (30-minute average for odour impact). These results indicate that
further investigation of the landfill’s impact on ambient air quality and human health is warranted.
Table 1: Field Measurement Results (µg/m3, 15-minute averaging period)
Concentrations Measured in Ambient Air (µg/m3)
Compound
G0129825
G0129891
Benzene
<RL*
3667
Ethylbenzene
1010
1210
m/p-xylene
4003
4670
o-xylene
1710
2177
Styrene
1377
1343
Tetrachloroethene
367
300
Toluene
1700
2033
*Below reporting limit (~3500 µg/m3)
TCEQ ESL
(µg/m3)
170
26000
2200
2200
110
2000
4500
Table 2: Field Measurements (ppbv, 15-minute averaging period)
Concentrations Measured in Ambient Air (ppbv)
Compound
G0129825
G0129891
Benzene
<RL*
1147.73
Ethylbenzene
232.59
278.65
m/p-xylene
922.01
1075.56
o-xylene
393.83
501.31
Styrene
323.18
315.36
Tetrachloroethene
54.06
44.23
Toluene
451.10
539.56
*Below reporting limit (~1000 ppbv)
**Inhibited
Odour Threshold2
(ppbv)
4680
NA
470
NA
100**
4680
2140
1
WHO (World Health Organisation) (2000): Air Quality Guidelines for Europe, Copenhagen, 273 pp.
Leonardos, G.; Kendall, D. & Barnard, N. (1969). Odor Threshold Determinations of 53 Odorant Chemicals in
Journal of the Air Pollution Control Association, 19:2, 91-95, DOI: 10.1080/00022470.1969.10466465
2
2
Measured concentrations of the volatile organic compounds were compared with the odour
thresholds published in Leonardos et al. (1969)3 with the understanding that there is often a wide
range of published odour thresholds for these compounds. The concentrations of m/p-xylenes
measured by G0129825 and G0129891 exceeded the odour threshold (470 ppmv). The
concentrations of styrene measured by G0129825 and G0129891 also exceeded the respective
odour threshold (100 ppmv), suggesting odour nuisance by volatile organic compounds beyond the
boundary of the site. Further investigation of odour impacts by volatiles from the site clearly is
warranted.
Some discrepancies between the WSP results and those of the 15 hydrocarbon samples collected
by Infotox on the Enviroserv site (Annexure 3 to Infotox Report dated 10 April 2017) are noted here.
The maximum benzene concentration measured onsite (890 µg/m3) by Infotox was at the brine
tank. This concentration falls below our fenceline measurement G0129891 (3667 µg/m3). The
maximum styrene concentration measured onsite (414 µg/m3) at Sample 15 (a landfill gas canister)
fall below our measurements G0129825 (1377 µg/m3) and G0129891 (1343 µg/m3). The maximum
concentration of tetrachloroethene measured onsite (125 µg/m3) at Sample 26 (another landfill gas
canister) falls below our measurements G0129825 (367 µg/m3) and G0129891 (300 µg/m3).
We are confident that the source of the volatile organic compounds we measured was the
Enviroserv landfill site because the intensity of the hydrocarbon odour increased as we moved
closer to the Enviroserv fenceline. One does not expect offsite measurements to be higher than
measurements at the source, as is the case here. It appears that further onsite measurements are
required since the current data collected by Infotox may be an underestimate of the real impact of
the site. We have greater confidence in the volatile organic compound measurements at the
Enviroserv landfill site by re-energise Africa in partnership with Siloxa Engineering AG (report dated
27 February 2017) as Annexure S of the Final Envitech Report (dated 14 March 2017). Should the
Infotox concentrations be underestimates of real impact, this would in turn bring into question the
atmospheric dispersion modelling results produced by Airshed.
We do not view our fenceline samples presented here indicative of peak ambient pollutant
concentrations associated with the landfill emissions. Odour complaints tend to peak during lowpressure events, particularly during rainy or misty conditions. The weather was clear during our
sampling. Furthermore, the higher turbulence associated with early afternoon sunshine is likely to
promote vertical dispersion of pollutants, lowering ground-level concentrations relative to stable
overnight conditions. The concentrations we present here are the most conservative of our recent
monitoring campaigns. We expect that future testing will confirm significantly higher ambient
concentrations of volatile organic compounds at the fenceline, particularly under pre-frontal
conditions and/or overnight.
Yours faithfully,
Dr Lisa Frost Ramsay
Air Quality Specialist
3
Leonardos, G.; Kendall, D. & Barnard, N. (1969). Odor Threshold Determinations of 53 Odorant Chemicals in
Journal of the Air Pollution Control Association, 19:2, 91-95, DOI: 10.1080/00022470.1969.10466465
3